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  <title>Document</title>
  <script>
    //new 正则表达式对象
    var phoneReg  = /^1[3|5|7|8|9]\d{9}$/
    var phone = "23813912345"
    var flag = phoneReg.test(phone) 
    console.log("==========="+flag)
  </script>
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<body>
  
</body>
</html>